The present disclosure relates generally to cooking appliances, and in particular to controlling a bake cooking cycle in an oven cavity of a gas cooking appliance.
Generally, cooking appliances such as gas ranges, cycle a single heat source during a bake cooking cycle within an oven cavity of the cooking appliance. This single heat source is generally positioned at a bottom of the oven cavity and beneath the items being baked. The cycling of a single heat source located beneath the items may result in uneven cooking. For example, since the heat source is located beneath the items, the bottom of the items may be seared or browned while the top(s) of the items remain substantially free from browning.
In a typical gas oven appliance, an electronic ignition system is used to ignite the gas supply of the oven. As will be understood in the art, a hot surface or “glow bar” type oven igniter or system is commonly used to ignite the gas supply in the oven. In these types of systems, the oven igniter and gas valve circuit are connected in series. As power flows through the oven igniter, the igniter heats up. When the oven igniter reaches a predetermined ignition temperature, the oven gas valve will open, allowing gas to flow from the burner. The glowing hot oven igniter will ignite the gas flow.
However, if the supply power or voltage to the oven igniter varies or fluctuates, as is common with household electric power supplies, the time required for the oven igniter to reach the predetermined ignition temperature can also fluctuate. In a typical situation, it can take on average between 30 to 90 seconds for the oven igniter to reach the predetermined ignition temperature and open the gas valve and ignite the gas at the oven burner. However, in the case of a drop in the supply voltage or power, the time required for the oven igniter to reach the predetermined ignition temperature can increase.
Certain gas oven cooking algorithms typically rely upon timed ON and OFF cooking algorithms, commonly referred to as bake and broil cycles. However, these timed cooking algorithms are susceptible to inconsistent cooking performance due to the variable input voltages to the ignition system in a gas powered range. If the time needed for the oven igniter to reach the predetermined ignition temperature is longer than anticipated by the timed cooking cycle, the actual cooking time may be adversely impacted.
As an example, an average time for a typical oven igniter to reach the predetermined ignition temperature at a nominal input power supply voltage of 120 VAC, can be in the range of approximately 30-90 seconds. One example of such an oven igniter is the Oven GlowBar Part Number 223C3381 manufactured by Saint-Gobain Igniter Products of Milford, N.H. (formerly Norton Igniter Products). However, if the input power supply voltage drops, to for example approximately 102 volts, the oven igniter will take a longer time to heat up and open the gas valve than it would at the nominal voltage. Thus, variations in the input voltage can result in variable oven flame ignition times, which directly affects consistency and quality of cooking performance. As noted above, if the input voltage to the glow bar oven igniter is lower than the nominal rated value, the period of time is required for the glow bar igniter to heat up and open the gas valve can be longer than the burner ON time. This can result in little or no heat being supplied during normal operating conditions and a rapid recovery cooking algorithm will be relied upon to maintain the oven cavity temperature. The term “rapid recovery” generally refers to a cooking algorithm that is used to increase the oven temperature back to the set point when the temperature of the oven cavity falls below a predetermined amount below the set point and normal cooking operation is not able to stabilize the temperature. This results in generally poor cooking performance. It would be advantageous to be able to utilize multiple heat sources for a cooking algorithm in a gas oven cavity that reduces input voltage susceptibility and enables more consistent cooking performance and food browning to address the problems identified above.